Re: [PATCH V6 16/21] soc/tegra: pmc: Add pmc wake support for tegra210

Dmitry Osipenko
2019-07-23T01:41:46Z

23.07.2019 4:08, Dmitry Osipenko пишет:
> 23.07.2019 3:58, Dmitry Osipenko пишет:
>> 21.07.2019 22:40, Sowjanya Komatineni пишет:
>>> This patch implements PMC wakeup sequence for Tegra210 and defines
>>> common used RTC alarm wake event.
>>>
>>> Signed-off-by: Sowjanya Komatineni <skomatineni@nvidia.com>
>>> ---
>>> drivers/soc/tegra/pmc.c | 111 ++++++++++++++++++++++++++++++++++++++++++++++++
>>> 1 file changed, 111 insertions(+)
>>>
>>> diff --git a/drivers/soc/tegra/pmc.c b/drivers/soc/tegra/pmc.c
>>> index 91c84d0e66ae..c556f38874e1 100644
>>> --- a/drivers/soc/tegra/pmc.c
>>> +++ b/drivers/soc/tegra/pmc.c
>>> @@ -57,6 +57,12 @@
>>> #define PMC_CNTRL_SYSCLK_OE BIT(11) /* system clock enable */
>>> #define PMC_CNTRL_SYSCLK_POLARITY BIT(10) /* sys clk polarity */
>>> #define PMC_CNTRL_MAIN_RST BIT(4)
>>> +#define PMC_CNTRL_LATCH_WAKEUPS BIT(5)
>
> Please follow the TRM's bits naming.
>
> PMC_CNTRL_LATCHWAKE_EN
>
>>> +#define PMC_WAKE_MASK 0x0c
>>> +#define PMC_WAKE_LEVEL 0x10
>>> +#define PMC_WAKE_STATUS 0x14
>>> +#define PMC_SW_WAKE_STATUS 0x18
>>>
>>> #define DPD_SAMPLE 0x020
>>> #define DPD_SAMPLE_ENABLE BIT(0)
>>> @@ -87,6 +93,11 @@
>>>
>>> #define PMC_SCRATCH41 0x140
>>>
>>> +#define PMC_WAKE2_MASK 0x160
>>> +#define PMC_WAKE2_LEVEL 0x164
>>> +#define PMC_WAKE2_STATUS 0x168
>>> +#define PMC_SW_WAKE2_STATUS 0x16c
>>> +
>>> #define PMC_SENSOR_CTRL 0x1b0
>>> #define PMC_SENSOR_CTRL_SCRATCH_WRITE BIT(2)
>>> #define PMC_SENSOR_CTRL_ENABLE_RST BIT(1)
>>> @@ -1922,6 +1933,55 @@ static const struct irq_domain_ops tegra_pmc_irq_domain_ops = {
>>> .alloc = tegra_pmc_irq_alloc,
>>> };
>>>
>>> +static int tegra210_pmc_irq_set_wake(struct irq_data *data, unsigned int on)
>>> +{
>>> + struct tegra_pmc *pmc = irq_data_get_irq_chip_data(data);
>>> + unsigned int offset, bit;
>>> + u32 value;
>>> +
>>> + if (data->hwirq == ULONG_MAX)
>>> + return 0;
>>> +
>>> + offset = data->hwirq / 32;
>>> + bit = data->hwirq % 32;
>>> +
>>> + /*
>>> + * Latch wakeups to SW_WAKE_STATUS register to capture events
>>> + * that would not make it into wakeup event register during LP0 exit.
>>> + */
>>> + value = tegra_pmc_readl(pmc, PMC_CNTRL);
>>> + value |= PMC_CNTRL_LATCH_WAKEUPS;
>>> + tegra_pmc_writel(pmc, value, PMC_CNTRL);
>>> + udelay(120);
>>
>> Why it takes so much time to latch the values? Shouldn't some status-bit
>> be polled for the completion of latching?
>>
>> Is this register-write really getting buffered in the PMC?
>>
>>> + value &= ~PMC_CNTRL_LATCH_WAKEUPS;
>>> + tegra_pmc_writel(pmc, value, PMC_CNTRL);
>>> + udelay(120);
>>
>> 120 usecs to remove latching, really?
>>
>>> + tegra_pmc_writel(pmc, 0, PMC_SW_WAKE_STATUS);
>>> + tegra_pmc_writel(pmc, 0, PMC_SW_WAKE2_STATUS);
>>> +
>>> + tegra_pmc_writel(pmc, 0, PMC_WAKE_STATUS);
>>> + tegra_pmc_writel(pmc, 0, PMC_WAKE2_STATUS);
>>> +
>>> + /* enable PMC wake */
>>> + if (data->hwirq >= 32)
>>> + offset = PMC_WAKE2_MASK;
>>> + else
>>> + offset = PMC_WAKE_MASK;
>>> +
>>> + value = tegra_pmc_readl(pmc, offset);
>>> +
>>> + if (on)
>>> + value |= 1 << bit;
>>> + else
>>> + value &= ~(1 << bit);
>>> +
>>> + tegra_pmc_writel(pmc, value, offset);
>>
>> Why the latching is done *before* writing into the WAKE registers? What
>> it is latching then?
>
> I'm looking at the TRM doc and it says that latching should be done
> *after* writing to the WAKE_MASK / LEVEL registers.
>
> Secondly it says that it's enough to do:
>
> value = tegra_pmc_readl(pmc, PMC_CNTRL);
> value |= PMC_CNTRL_LATCH_WAKEUPS;
> tegra_pmc_writel(pmc, value, PMC_CNTRL);
>
> in order to latch. There is no need for the delay and to remove the
> "LATCHWAKE_EN" bit, it should be a oneshot action.

Although, no. TRM says "stops latching on transition from 1
to 0 (sequence - set to 1,set to 0)", so it's not a oneshot action.

Have you tested this code at all? I'm wondering how it happens to work
without a proper latching.

>>> + return 0;
>>> +}
>>> +
>>> static int tegra186_pmc_irq_set_wake(struct irq_data *data, unsigned int on)
>>> {
>>> struct tegra_pmc *pmc = irq_data_get_irq_chip_data(data);
>>> @@ -1954,6 +2014,49 @@ static int tegra186_pmc_irq_set_wake(struct irq_data *data, unsigned int on)
>>> return 0;
>>> }
>>>
>>> +static int tegra210_pmc_irq_set_type(struct irq_data *data, unsigned int type)
>>> +{
>>> + struct tegra_pmc *pmc = irq_data_get_irq_chip_data(data);
>>> + unsigned int offset, bit;
>>> + u32 value;
>>> +
>>> + if (data->hwirq == ULONG_MAX)
>>> + return 0;
>>> +
>>> + offset = data->hwirq / 32;
>>> + bit = data->hwirq % 32;
>>> +
>>> + if (data->hwirq >= 32)
>>> + offset = PMC_WAKE2_LEVEL;
>>> + else
>>> + offset = PMC_WAKE_LEVEL;
>>> +
>>> + value = tegra_pmc_readl(pmc, offset);
>>> +
>>> + switch (type) {
>>> + case IRQ_TYPE_EDGE_RISING:
>>> + case IRQ_TYPE_LEVEL_HIGH:
>>> + value |= 1 << bit;
>>> + break;
>>> +
>>> + case IRQ_TYPE_EDGE_FALLING:
>>> + case IRQ_TYPE_LEVEL_LOW:
>>> + value &= ~(1 << bit);
>>> + break;
>>> +
>>> + case IRQ_TYPE_EDGE_RISING | IRQ_TYPE_EDGE_FALLING:
>>> + value ^= 1 << bit;
>>> + break;
>>> +
>>> + default:
>>> + return -EINVAL;
>>> + }
>>> +
>>> + tegra_pmc_writel(pmc, value, offset);
>>
>> Shouldn't the WAKE_LEVEL be latched as well?
>>
>>> + return 0;
>>> +}
>>> +
>>> static int tegra186_pmc_irq_set_type(struct irq_data *data, unsigned int type)
>>> {
>>> struct tegra_pmc *pmc = irq_data_get_irq_chip_data(data);
>>> @@ -2540,6 +2643,10 @@ static const struct pinctrl_pin_desc tegra210_pin_descs[] = {
>>> TEGRA210_IO_PAD_TABLE(TEGRA_IO_PIN_DESC)
>>> };
>>>
>>> +static const struct tegra_wake_event tegra210_wake_events[] = {
>>> + TEGRA_WAKE_IRQ("rtc", 16, 2),
>>> +};
>>> +
>>> static const struct tegra_pmc_soc tegra210_pmc_soc = {
>>> .num_powergates = ARRAY_SIZE(tegra210_powergates),
>>> .powergates = tegra210_powergates,
>>> @@ -2557,10 +2664,14 @@ static const struct tegra_pmc_soc tegra210_pmc_soc = {
>>> .regs = &tegra20_pmc_regs,
>>> .init = tegra20_pmc_init,
>>> .setup_irq_polarity = tegra20_pmc_setup_irq_polarity,
>>> + .irq_set_wake = tegra210_pmc_irq_set_wake,
>>> + .irq_set_type = tegra210_pmc_irq_set_type,
>>> .reset_sources = tegra210_reset_sources,
>>> .num_reset_sources = ARRAY_SIZE(tegra210_reset_sources),
>>> .reset_levels = NULL,
>>> .num_reset_levels = 0,
>>> + .num_wake_events = ARRAY_SIZE(tegra210_wake_events),
>>> + .wake_events = tegra210_wake_events,
>>> };
>>>
>>> #define TEGRA186_IO_PAD_TABLE(_pad) \
>>>
>>
>